A Phase 1, open-label, non-randomized, dose-escalation study, where approximately 18 eligible patients with retinitis pigmentosa or choroideremia will be enrolled sequentially in up to 4 dose cohorts of RTx-015. Enrolled patients will receive a single, unilateral intravitreal injection of RTx-015 in the study eye at Visit 3 (Day 0) and be followed for a total of 5 years.

This Phase 1, open-label, non-randomized, multicenter clinical trial is to evaluate the safety and preliminary efficacy of a single, uniocular intravitreal injection of an investigational optogenetic gene therapy, RTx-015, in patients with retinitis pigmentosa or choroideremia. Up to 4 dose cohorts are planned, and each cohort will consist initially of 3 patients. Eligible patients will be assigned to a dose cohort by sequential enrollment.

Inclusion Criteria:

• Adults ≥18 years of age
• Informed consent obtained from the patient
• Clinical diagnosis of Retinitis Pigmentosa independent of causative mutation OR Clinical diagnosis of Choroideremia with known causative mutation
• Study eye and fellow eye Best Corrected Visual Acuity meeting study criteria
• Presence of retinal ganglion cells and/or retinal nerve fiber layer on Spectral Domain Optical Coherence Tomography testing at Screening confirmed by central image reading center
• Adequate organ function and general good health

Exclusion Criteria:

• Participation in a clinical study (ocular or non-ocular) with an investigational drug, agent, or therapy in the past six months
• Concurrent participation in another interventional clinical ocular study
• Prior receipt of any gene therapy (ocular or other), retinal implant, or ocular cell therapy
• Pre-existing eye conditions in either eye that would preclude the planned treatment or, in the opinion of the Investigator, are significant enough to interfere with the interpretation of study endpoints or procedural complications
• Known steroid responders if their intraocular pressure was not able to be managed effectively with topical pressure-lowering medications after prior use of steroid medications
• Complicating systemic diseases; complicating systemic diseases include those in which the disease itself, or the treatment for the disease, can alter ocular and/or Central Nervous System (CNS) function (e.g., radiation treatment of the orbit; leukemia with CNS/optic nerve involvement)
• Any immunological response dysfunction including, immuno-compromising diseases or use of immunosuppressive medications, among others
• Cataract or other ocular (including refractive) surgery, intraocular and/or peri-ocular injection in either eye within the prior four months (i.e., 120 days) prior to screening
• Prior vitrectomy or aphakia in the study eye
• Known sensitivity to any component of the study treatment or contraindication to medications planned for use in the peri-procedural period (e.g., povidone-iodine to prep for intravitreal injection)
• Known contraindication to prophylactic steroid regimen
• Current pregnancy or breastfeeding
• Any other condition that would not allow the patient to complete follow-up examinations during the study